A. Field of the Invention
The field of the present invention relates generally to air suspension systems for motorcycles and bicycles. More particularly, the present invention relates to vehicle air suspension systems that utilize one or more pneumatic shock absorbers hydraulically connected to a source of air on the motorcycle or bicycle to provide improved shock absorbing effect. Even more particularly, the present invention relates to such air suspension systems that utilize an integrated tubular component as the source of air.
B. Background
Motorcycles and bicycles are generally configured with a front fork that interconnects the handle bar of the motorcycle or bicycle with the front wheel. Most motorcycles and many bicycles, particularly those utilized for off-road racing and cross-country sporting competitions, comprise a front suspension system that is intended to improve the stability, rideability and steering properties of the motorcycle or bicycle, particularly on the generally rough track or path utilized for motorcycle or bicycle racing. The typical front suspension system comprises a pair of independent shock absorber devices, each having a shock-damper assembly, that cooperate with or are incorporated into (most common) the front forks of the motorcycle or bicycle. In the past, front suspension systems for motorcycles and bicycles basically comprised just the shock absorbers, which were generally configured with a piston component that divided the shock absorber cylinder or fork into two chambers, an upper chamber and a lower chamber, in which the piston reciprocated to compress a fluid, such as oil. A piston rod interconnects one end of the piston with either the wheel assembly or a portion of the frame of the motorcycle or bicycle. A spring is generally utilized with the shock absorber to provide additional damping. A trunnion connects the other end of the shock absorber to either the wheel assembly or a portion of the frame of the motorcycle/bicycle. As the piston reacts to the impact force imparted on the wheel from the road, track or path, fluid from the upper chamber flows to the lower chamber and the spring compresses to dampen the impact.
As known to those skilled in the art, more modern suspension systems utilize the front forks as part of the suspension system. Air contained in the front fork acts as an additional spring that, when compressed, further resists the impact force on the front wheel. In general, the more air volume that is available in the shock absorber the softer the ride will be and the less air volume in the shock absorber the more resistant the system will be to “bottoming out” the forks. The resistance in the small air volume systems increases rapidly, thereby making the suspension harsh on the initial portion of the stroke (i.e., small bumps). Because the amount of air in the system affects the ride (handling versus smoothness of the ride), the front forks are typically provided with two air tight caps on the closed upper end of the fork that have an air-release bleed screw in the caps to allow the user to bleed air from the shock absorber to release the build-up of air pressure therein. Unfortunately, it is generally impossible to utilize the air-release bleed screws to adjust the suspension system while the motorcycle is being utilized.
To improve on the stability, rideability and overall handling of the motorcycle or bicycle, many riders utilize an additional air storage system that is outfitted with controls that allows them to better adjust the ride and handling of the motorcycle/bicycle. A variety of such systems are available for use. The typical air tank system comprises an air tank or air bottle mounted on the motorcycle/bicycle that is connected to the fork's air port via a hose, which is generally a stainless steel hose. Most such systems also include a bleed screw or other adjusting valve having an adjustable orifice that controls airflow in both directions to allow the rider to adjust the amount of air that transfers between the front forks and the air tank. Typically, any such air tank or tanks are attached directly to the front forks, adjacent to or near the motorcycle's engine, on the frame or above the front forks on the handlebar assembly (i.e., behind the front number plate). Examples of air tank suspension systems currently available include those from Too Tech Racing, Tech-Care and Moto Pro Suspension. Various United States patents also describe pneumatic suspension systems for motorcycles and bicycles, including U.S. Pat. No. 4,275,900 to Andreoli, U.S. Pat. No. 4,732,244 to Verkuylen, U.S. Pat. No. 5,209,319 to Buell, U.S. Pat. No. 6,311,961 to Julia, U.S. Pat. No. 6,520,524 to Costa, U.S. Pat. No. 6,533,305 to Falk and U.S. Pat. No. 6,611,743 to Sakai, the disclosures of which are incorporated herein by reference.
The presently available air tank suspension systems have a number of limitations. One of the primary limitations is the additional weight of the air tank that must be carried on the motorcycle/bicycle. As is well known, many motorcycle and bicycle riders, particularly competitive riders, are willing to spend money to purchase components for their motorcycle or bicycle that are made out of lighter weight materials, such as titanium and carbon fiber, so as to reduce the vehicle's weight. Unfortunately, in order to obtain the benefits of the presently available air tank suspension systems, the rider is required to add weight to his or her motorcycle or bicycle. From a rider's standpoint, particularly those serious about performance, the additional weight is not insignificant. Another limitation of the presently available air tank suspension systems is the placement of the air tank on the motorcycle or bicycle. If the air tank is not securely mounted on the motorcycle or bicycle, it can shake loose and fall off, which can damage the tank or even the motorcycle or bicycle itself, particularly those systems that utilize tanks that attach to the front fork or at the handlebar assembly. Another limitation of presently available air tank suspension systems is the fact that most such systems do not allow the rider to easily adjust the air flow while he or she is riding, which is often when it is most needed. The typical air suspension system uses an automotive-type valve stem that requires the use of manual tools to release air.
What is needed is an air suspension system for vehicles such as motorcycles and bicycles that solves the problems and provides the benefits described above. The preferred air suspension system should be configured to provide the benefits of additional air storage for the front fork suspension system of the motorcycle or bicycle without the additional weight issues associated with presently available air suspension systems. The preferred air suspension system should allow the rider to easily and safely adjust the amount of air flow to and from the front fork to adjust the damping effect thereof while he or she is riding the motorcycle or bicycle. The preferred air suspension system should also be both economical to manufacture and use and be adaptable for retrofit to many existing suspension systems.